<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>父子</title>
    <style>
        .box{
            width:200px;
            height:200px;
            background-color: yellow;
            position:absolute;
            top:100px;
            left:200px;
        }
        .box1{
            width:100px;
            height:100px;
            background-color: black;
            position:absolute;
            left:500px;
            top:300px;
        }
        .big{
            width:500px;
            height:500px;
            background-color: #3e999f;
        }
    </style>
</head>
<body>
<div class="big">
    <div class="box">
        <div class="box1"></div>
    </div>
</div>
<script>
    //如果父元素，不管怎么样都是一样的位置，子元素如果是absolute,相对于父元素定位，则按父元素来算，
    //固定定位按照浏览器来看
</script>
<script>

</script>
</body>
</html>